"""
列表的常用操作案例
"""
student_age_list = [21, 25, 21, 23, 22, 20, 31]
print("添加元素31后:", student_age_list)
student_age_list1 = [29,33,30]
student_age_list.extend(student_age_list1)
print("扩展列表后:", student_age_list)
print("第一个元素:", student_age_list[0])
print("最后一个元素:", student_age_list[-1])
index_31 = student_age_list.index(31)
print("元素30的索引:", index_31)